Hoisting frame and method for its use

ABSTRACT

A hoisting frame that can be connected at an upper side to hoisting cables and have a device on an underside for picking up a secondary hoisting frame. The hoisting frame may be adjustable between a retracted position, in which its transverse dimension is equal to that of the secondary hoisting frame, and an extended position. Pick-ups are adapted to pick up a single secondary hoisting frame in the retracted position and to pick up two mutually adjacent secondary hoisting frames in the extended position. A method for transferring containers may include picking up one load at a first location when the hoisting frame is retracted, or two loads when the hoisting frame is extended, lifting, displacing to a second location and then lowering the hoisting frame with the picked-up load(s), uncoupling the load(s) from the hoisting frame, lifting the hoisting frame, moving the hoisting frame from one to another position. A secondary hoisting frame may be coupled or uncoupled and the steps repeated.

The invention relates to a hoisting frame, provided with means arrangedon the upper side for connecting thereof to at least two hoisting cablessuspended at a mutual distance in longitudinal direction of the hoistingframe and means arranged on the underside for picking up at least onesecondary hoisting frame. Such a hoisting frame is generally known andis applied particularly for transferring containers from a ship to aquay or vice versa.

Increasingly greater demands are being made on the capacity of hoistingframes for use in the transfer of containers. The use of containers intransport does after all continue to increase, while the price which canbe asked for the transport is relatively low as a result of the greatcompetition. The transport of containers must therefore be carried outas efficiently as possible. An important overhead in this respect is theloading and unloading of containers, since a ship lying at quayside isvery expensive. Possibilities for increasing the transfer speed aretherefore continually being sought. One problem here is that containerships are becoming increasingly larger, both in height and in width. Thetime involved in hoisting and lowering containers out of and into thehold of the ship and in displacing the containers from the ship to thequay and vice versa therefore continues to increase.

It has therefore already been proposed to pick up a plurality ofcontainers in one movement. Applicant has himself already proposed ahoisting frame with which two containers placed adjacently inlongitudinal direction, i.e. with their end surfaces mutually abutting,can be picked up in one movement and the distance between the containerscan optionally be adjusted during the trajectory, as described inWO-A-97/39973.

In addition, it is also already known to pick up in one movement twocontainers mutually abutting on the long side. Use is made for thispurpose of a hoisting frame from which are suspended two mutuallyadjacent sub-frames which can each pick up a container. This knownhoisting frame, which is described in WO-A-01/98195, comprises twolongitudinal beams which are connected at their ends by two cross beams,from which the sub-frames or secondary hoisting frames are movablysuspended. For the movement of the secondary hoisting frames, which cantake the form of conventional hoisting frames or “spreaders” adjustablein longitudinal direction, use is made of trolleys which aredisplaceable along the cross beams and from which the spreaders aresuspended via rods or chains. The cross beams of the main frame are eachsuspended from a hoisting block which has two cable pulleys forco-action with a pair of hoisting cables. In order to compensate forasymmetrical suspending of the hoisting frame as a result of an unevenload, for instance due to a difference in the weight of the two liftedcontainers, each hoisting block is displaceable in transverse directionalong the cross beam under the influence of a hydraulic cylinder or thelike.

This known hoisting frame has the drawback that the dimensions thereofmust be relatively large in transverse direction in order to enablesuspending of both the spreaders thereunder in stable manner. Thedimensions in transverse direction are in any case larger than those ofa single container or spreader. It is therefore not possible with thisknown hoisting frame to pick up a single container when this containeris not situated in the top layer of containers on a ship. In that casethe hoisting frame must be uncoupled from the hoisting blocks and bereplaced by a conventional single spreader which can be carried downwardbetween two stacks of containers. The same change is required when thenumber of containers adjacently of each other in a layer is uneven and asingle container is thus finally left standing. Exchanging the hoistingframe and a standard spreader requires a number of extra operations,whereby a part of the time-saving achieved by picking up the containerstwo at a time is lost. In addition, the hoisting frame takes up verymuch space when temporarily not in use, which space is scarce andexpensive on the quay in the vicinity of the container crane. Feeder anddischarge roads to the crane, which heretofore have been designed forthe width of a single container, must also be adjusted to the largerwidth of the hoisting frame.

Another drawback of the known hoisting frame is that during hoisting ofcontainers out of the hold of a ship, wherein as a result of thefriction between the guides present therein and the containers varyingvertical loads are exerted on the hoisting frame, the hoisting framewill start to swing out of control. In the worst case one of thecontainers can even become jammed in its guide, whereby the hoistingframe is pulled out of alignment and the hoisting cables will becomecaught in the pulleys. Because the crane which hauls in the hoistingcables does not come to an immediate stop in the case of such overload,but still has a determined braking distance, there is the chance thatthe hoisting frame with the containers hereby becomes so jammed that thehoisting frame has to be released from the hoisting blocks and remainsbehind in the hold.

The invention therefore has for its object to provide a hoisting frameof the above described type, wherein these drawbacks do not occur. Thisis achieved according to the invention in that the frame is adjustablein transverse direction between a retracted position, in which itstransverse dimension is at most equal to that of the secondary hoistingframe, and an extended position in which its transverse dimension islarger than that of the secondary hoisting frame, and the pick-up meansare adapted to pick up a single secondary hoisting frame in theretracted position and to pick up two mutually adjacent secondaryhoisting frames in the extended position. By giving the frame anadjustable form in transverse direction such that it has a minimaldimension which is smaller than that of a spreader or container, it issuitable for processing single containers as well as two containerssimultaneously, wherein single containers can also be processed whenthey are not positioned in the upper layer.

An effective construction is achieved when the frame is divided inlongitudinal direction, the frame parts are movable relative to eachother at least in transverse direction and the pick-up means comprise anumber of pick-up elements distributed over the frame parts. The desiredmovements can thus be achieved in simple manner.

The hoisting frame herein preferably has controllable means for movingthe frame parts away from and toward each other. These moving means canadvantageously comprise at least one member of adjustable length whichconnects the frame parts, wherein the frame parts can be moved away fromor towards each other by adjusting the length of the connecting member.

The moving means further preferably comprise at least one actuatorco-acting with the at least one connecting member. The movements canhereby be driven.

A robust and compact construction is obtained when the at least oneconnecting member is a pivotable arm. A pivoting movement can moreoverbe driven and controlled in simple manner, and the risk of a pivotbecoming jammed is smaller than in the case of a linear movement along aguide. The arm is herein advantageously pivotable substantially parallelto a main plane of the hoisting frame. In this manner the constructionheight of the hoisting frame remains limited.

In order to reduce the loads on the frame part the at least onepivotable arm can be connected to the frame part via a pivot and theactuator can be arranged between the arm and the pivot. Loads are thustransmitted via the shortest possible route.

In order to enable proper control of the movements of the hoistingframe, this latter preferably has at least two pivotable arms which areeach moved by at least one associated actuator. For a preciselydetermined movement at least two actuators are advantageously connectedto at least one of the pivotable arms.

An even distribution of the loads on the hoisting frame is achieved whenthe pivotable arms are arranged substantially symmetrically relative toa transverse centre line of the hoisting frame, and the arms on oppositesides of the hoisting frame are pivotable in opposite directions.

Likewise with a view to an even distribution of the loads and fromproduction considerations, it is recommended that each pivotable arm issubstantially symmetrical relative to a longitudinal centre line of thehoisting frame. Identical arm parts can thus be used.

For a stable movement of the frame parts it is recommended that theconnecting means are adapted to connect the hoisting frame to at leasttwo pairs of hoisting cables suspended at a distance from each other inlongitudinal direction of the hoisting frame, and are divided inlongitudinal direction such that each frame part can be connected to atleast two hoisting cables. The connecting means can herein comprisecable pulleys, and each frame part can advantageously carry at least twocable pulleys placed at a distance from each other in longitudinaldirection.

For a uniform loading of the hoisting means the pick-up elements arepreferably placed substantially straight under the cable pulleys in theextended position of the hoisting frame.

In order to increase the flexibility of the hoisting frame duringpicking up and setting down of the loads, the frame is advantageouslyadjustable in transverse direction in the extended position in order tovary a space between the two secondary hoisting frames.

When the frame parts are pivotable relative to each other in the planeof the hoisting frame, loads can also be picked up which are not placedprecisely parallel to each other.

In order to allow loads to be picked up or set down on an irregularsurface, the frame parts are further preferably pivotable relative toeach other transversely of the plane of the hoisting frame. The hoistingframe can herein be provided with at least one actuator arranged betweena rotation axis of one of the cable pulleys and the frame part, wherebythe pivoting movement can be effected.

The frame parts are further preferably movable relative to each other inlongitudinal direction in order to allow picking up of loads which donot lie precisely in one line.

The or each secondary hoisting frame is advantageously also adjustablein longitudinal direction, whereby loads of different length, forinstance containers in the sizes 20 feet, 30 feet, 40 feet and 45 feet,can be picked up.

The invention further relates to a method for transferring loads, suchas containers, which comprises the steps of:

a) lowering a hoisting frame according to any of the foregoing claims ata first location,

b) picking up one load at the first location when the hoisting frame isretracted, or two loads when the hoisting frame is extended,

c) lifting the hoisting frame with the picked-up load(s),

d) displacing the hoisting frame with the picked-up load(s) to a secondlocation,

e) lowering the hoisting frame with the picked-up load(s) at the secondlocation,

f) uncoupling the load(s) from the hoisting frame,

g) lifting the hoisting frame,

h) moving the hoisting frame from its retracted to its extended positionor from its extended to its retracted position, wherein a secondaryhoisting frame is coupled on or uncoupled, and

i) repeating steps (a) to (g).

With such a method it is readily possible to switch from transferringsingle containers to transferring two containers at a time, and viceversa.

The invention will now be elucidated on the basis of a number ofembodiments, wherein reference is made to the annexed drawing, in which:

FIG. 1 is a perspective view of a hoisting frame according to a firstembodiment of the invention in the extended position, with two secondaryhoisting frames each carrying two containers,

FIG. 2 is a perspective view of the hoisting frame according to FIG. 1in the extended position,

FIG. 3 is a perspective view of the two secondary hoisting frames ofFIG. 1,

FIG. 4A is a front view along arrow IV in FIG. 1 of a hoisting frameaccording to a second embodiment of the invention in the fully extendedposition, wherein a space is left clear between two hoisting framessuspended therefrom,

FIG. 4B is a view corresponding with FIG. 4A of the hoisting frame inthe shortest extended position, wherein the secondary hoisting framessuspended therefrom make mutual contact,

FIG. 4C is a view corresponding with FIGS. 4A and 4B of the hoistingframe in its retracted position, wherein only a single hoisting frame issuspended thereunder,

FIG. 5A is a top view of the hoisting frame in its extended position,wherein the frame parts and the secondary hoisting frames mountedthereon enclose an angle in the plane of the hoisting frame,

FIG. 5B is a view corresponding with FIG. 5A in which the frame partsare shown in a position which is parallel but offset in longitudinaldirection,

FIG. 6 is a perspective view of a hoisting frame according to a thirdembodiment of the invention in the extended position,

FIG. 7A is a top view of a hoisting frame according to the embodimentshown in FIG. 6 in its retracted position, wherein only a singlehoisting frame with two containers is suspended thereunder,

FIG. 7B is a view corresponding with FIG. 7A of the hoisting frame inthe shortest extended position, wherein the secondary hoisting framesand containers suspended therefrom are in mutual contact,

FIG. 7C is a view corresponding with FIGS. 7A and 7B of the hoistingframe in the fully extended position, wherein a space is left clearbetween two hoisting frames and containers suspended therefrom,

FIG. 8A is a front view along VIII in FIG. 6 of the hoisting frameaccording to the invention with a secondary frame and container(s)thereunder,

FIGS. 8B and 8C are views corresponding with FIG. 8A of the hoistingframe with secondary frames and containers in respectively the shortestextended position and the fully extended position,

FIG. 9 is a top view of the hoisting frame in its extended position,wherein the frame parts and the secondary hoisting frames and containersmounted thereon enclose an angle in the plane of the hoisting frame,

FIG. 10 is a view corresponding with FIG. 9 wherein the frame parts areshown in a position which is parallel but offset in longitudinaldirection,

FIG. 11 is a front view of the hoisting frame in an extended position,wherein the frame parts are also pivoted transversely of the main planeof the hoisting frame, and

FIG. 12 is a view corresponding with FIG. 6 of a fourth embodiment ofthe hoisting frame according to the invention.

A hoisting frame 1 according to the invention comprises means 2 forconnection thereof to two pairs of hoisting cables 3 and means 4arranged on the underside for picking up one or two secondary hoistingframes or spreaders 5. In the shown embodiment the secondary hoistingframes or spreaders 5 are here so-called “Long Twin”™ spreaders asmarketed by applicant and described in WO-A-97/39973. Each spreader 5comprises in the usual manner a main beam 7, two slide beams 8 and, atthe end of each slide beam, a cross beam 28 which carries outer“twist-locks” 31. Arranged on main beam 7 are slidable saddles 9 whichcarry inner twist-locks 30. Twist-locks 30,31 co-act with openings or“corner castings” on the corners of containers 6 for coupling on oruncoupling of the containers.

Hoisting frame 1 is adjustable in transverse direction between aretracted position (FIG. 4C, 7A, 8A), in which the transverse dimensionthereof is at most equal to that of secondary hoisting frame 5 and thecontainer 6 carried thereby, and an extended position (FIG. 4A, 7B, 8B,4B, 7C, 8C) in which the transverse dimension of frame 1 is larger thanthat of a spreader 5 or a container 6. The pick-up means 4 on theunderside of hoisting frame 1, which are adapted to co-act withcorresponding coupling means 33 on the upper side of each spreader 5(FIG. 3), are embodied and dimensioned such that they can pick up asingle spreader 5 in the retracted position of hoisting frame 1, whilethey co-act with two spreaders 5 in the extended position.

The adjustability in transverse direction of hoisting frame 1 isachieved in the shown embodiment in that the hoisting frame 1 takes adivided form in longitudinal direction and is provided with controllablemeans 12 for moving frame parts 10 away from and towards each other. Inthe shown embodiment these moving means 12 comprise two members 13 ofadjustable length, here in the form of pivotable arms, which connect theframe parts. Each arm is herein formed by a part 13A which is mountedpivotally via a shaft 22 in a cradle 23 on one of the frame halves 10and a second part 13B which is connected to the first arm part 13A via apivot shaft 17. The second arm part 13B is mounted pivotally about ashaft 25 which is supported by a cradle 26 on the other frame half 10.For mounting of this arm part 13B use is made here of a ball joint 24,the purpose of which will be elucidated hereinbelow.

The means 2 for connecting hoisting frame 1 to hoisting cables 3comprise a number of cable pulleys 14 which are mounted in cradles 15for rotation about shafts 36. These connecting means 2 herein also takea divided form in the sense that each frame part 10 is provided with twocable pulleys 14 arranged at intervals in longitudinal direction for astable suspension thereof from hoisting cables 3.

The pick-up means 4 also take a divided form in longitudinal directionand are formed in the shown embodiment by four pick-up elements 11 inthe form of eyes protruding on the underside, through which can beplaced sliding pins 34 which form part of coupling means 33 of spreaders5. These pick-up elements 11 are herein placed substantially straightunder cable pulleys 14 in order to ensure a stable suspension. Astrengthened support part 35 is further formed on either side of eachpick-up element 11 in order to enable a moment resulting from anunevenly loaded container 6 to be absorbed.

Moving means 12 further comprise actuators 16 for moving the pivot arms13, in the shown embodiment in the form of hydraulic cylinders which runpractically parallel to arm parts 13B, in order to allow a large strokewithout taking up too much space in the retracted position of hoistingframe 1.

In addition to these actuators or drive cylinders 16, damping orstabilizing cylinders 18,19 are also connected to arm parts 13A,13B,which cylinders serve to counter swinging movements of each frame half10 round a longitudinal axis defined by shafts 36 of cable pulleys 14when a picked-up container is unevenly loaded or moves unevenly due tofriction in the hold of a ship. In addition to a passive damping action,the cylinders 18,19 can also function as actuator and be activelycontrolled to correct asymmetrical suspension of a frame part 10 as aresult of an uneven loading of a container 6. In addition, the inventionprovides that these actuators 18,19 are actively controlled to pivoteach frame part 10 around shafts 36 to a desired angle such thatcontainers 6 can be picked up from or set down on an uneven surface.

These damping cylinders 18,19 are each connected to a slide rod 20,21 onthe associated frame half 10, while the ball joints 24, with which thearm parts 13B are mounted around pivot shafts 25, are slidable alongthese shafts. One of the arm parts 13B is connected via a coupling piece37 to a cylinder 27 which runs in longitudinal direction and which isfixed to a cradle 32 on the relevant frame half 10.

In the shown embodiment the pivot shafts 22 and pivot shafts 25 areplaced substantially in one line with shafts 36 of the cable pulleys soas not to introduce any additional moments around these shafts 36 duringa movement of frame parts 10.

The above described arrangement of the pivot arms, the drive mechanismand the bearing enables a large number of movements of frame parts 10relative to each other, both parallel to the plane of hoisting frame 1and transversely thereof. When drive cylinders 16 are movedsynchronously, frame halves 10 are in principle moved apart intransverse direction and parallel to each other. Frame parts 10 can thusbe moved from the retracted to the extended position, but they can alsobe moved further apart from the extended position in order to form or tovary an intermediate space D between two lifted containers 6.

If one of the two drive cylinders 16 is extended or retracted less farthan the other and the cylinder 27 running in longitudinal direction isoperated simultaneously, non-parallel movements of the two frame parts10 are then possible. Frame parts 10 can for instance then be placed inthe plane of frame 1 at an angle ∀ relative to each other (FIG. 5A),whereby containers 6 which do not stand parallel to each other can bepicked up. It is also possible for frame halves 10 to be placed at anangle relative to each other transversely of the plane of the hoistingframe to allow containers 6 to be picked up which are not in whollyhorizontal position.

Finally, when drive cylinders 16 are moved synchronously but in additionthe longitudinal cylinder 27 is also operated, it is possible to movethe frame parts 10 in longitudinal direction relative to each other whencontainers must be picked up which are offset relative to each otherover a distance “O” (FIG. 5B).

In an alternative embodiment of hoisting frame 1 (FIG. 6), shafts 17, 22and 25 are positioned substantially transversely of a main plane ofhoisting frame 1 and thus run roughly parallel to hoisting cables 3.Arms 13 can therefore pivot substantially parallel to hoisting frame 1and transversely of hoisting cables 3. Arms 13 hereby take up relativelylittle space above hoisting frame 1. This is important because containerships are loaded increasingly higher but container cranes have a limitedheight, whereby the space between the crane jib and the ship is becomingincreasingly smaller. Furthermore, the arms 13 thus lie close to thecentre of gravity of frame 1. The arms 13 on either side of frame 1 arealso arranged symmetrically relative to a transverse centre line C_(L)-Tof frame 1 and pivot in opposite directions, whereby an evendistribution of the loads over hoisting frame 1 is achieved.

In the shown embodiment the arms 13 are also symmetrical relative to alongitudinal centre line C_(L)-L of frame 1, and arm parts 13A,13B areidentical.

For the mounting of arm parts 13A,13B use is once again made of pivots24 with a certain degree of flexibility in height direction. Pivots 17of arm 13 can also display such a flexibility in height direction, sothat movements transversely of the main plane of the hoisting frame arepossible.

In this embodiment the actuators 7,8,9 by which the arms 13 are movedlie in the plane of these arms 13. Actuators 7,8,9 are connected to oneof the frame parts 10 for movement with one end round vertical pivotshaft 27 via an elevation 11, while the other end of each actuator 7,8,9is connected to a point of engagement 12 roughly halfway along an armpart 13A,13B which can be operated thereby. The pivot connection 27between each actuator 7,8,9 and the associated elevation 11 is alsoslightly flexible in height direction so as to allow actuators 7,8,9 tofollow the movements of arms 13.

Pivots 17 and 24 of arms 13 and pivots 27 of actuators 7,8,9 can againbe embodied as ball joints. A more robust construction is howeverachieved when in any case the pivots 24,27 take the form of universaljoints with, in addition to the main pivot shaft 22,26 respectively 27,a secondary pivot shaft 28 respectively 29 lying transversely thereof.

In this embodiment the actuators 18,19 are each also connected at oneend to a rod 20 which is fixed non-rotatably to a corresponding shaft36, while the other end of actuator 18,19 engages on frame part 10.

All actuators 7,8,9,18,19 are embodied in the shown embodiment ashydraulic piston/cylinder units which can exert a relatively great forceat relatively small dimensions, and which can furthermore be operatedand fed from great distance in simple manner by means of hydrauliclines.

When in this embodiment the three actuators 7,8,9 are movedsynchronously, pivot arms 13 will be extended or folded up to the sameextent and frame halves 10 are thus moved away from or toward each othermutually parallel in transverse direction.

If the actuators 7,8 connected to one of the two pivot arms 13 areextended or retracted less far than the actuator 9 connected to theother arm 13, non-parallel movements of the two frame parts 10 are thenpossible.

Finally, when actuators 8,9 are moved synchronously and actuator 7 issimultaneously operated in the opposite direction, it is possible tomove the frame parts 10 in longitudinal direction relative to eachother.

In addition to the described movements in the plane of hoisting frame 1,limited movements transversely of this plane are also possible as aconsequence of the flexibility in pivots 17,24,27 in height direction.By extending or retracting the actuators 18,19 the frame halves 10 canthus be placed at an angle relative to each other transversely of theplane of the hoisting frame, so as to be able to pick up containers 6which are not in wholly horizontal position. Pivoting movements are notonly possible here round the longitudinal centre line C_(L)-L, but alsoround the transverse centre line C_(L)-T.

In yet another embodiment of hoisting frame 1 (FIG. 12) there are fouractuators 7,8,9,31, two for each arm 13. Actuators 7,8,9,31 are hereinnot mounted directly on a frame part 10 but mounted with one end on aprotruding part 30 of the pivot 24, embodied as universal joint, of thearm part 13A,13B controlled thereby. Each actuator 7,8,9,31 herebyautomatically follows the (slight) movements in height direction of theassociated arm part 13A,13B without having to be individually mountedfor movement in height direction. In addition, the force exerted by eachactuator 7,8,9,31 does not therefore have to be transmitted to arm 13via frame part 10 and pivot 24, but is transmitted directly to the arm,whereby the construction of frame part 10 can be lighter and simpler.

With the hoisting frame 1 according to the invention at least twocontainers at a time placed with their long side adjacently of eachother can thus be picked up, moved upward, displaced and set down againsimultaneously in simple, rapid and reliable manner. The transfercapacity of a crane provided with such a hoisting frame is herebypractically doubled.

However, in order to also allow use of the hoisting frame to lift singlecontainers when they are not situated in the uppermost layer ofcontainers, the hoisting frame 1 can be readily returned from itsextended position to its retracted position. For this purpose one of thespreaders 5 is first uncoupled from the frame half 10 from which it issuspended by means of connecting pin 11, and set down somewhere it doesnot hinder the further hoisting operations. A place will often bereserved in the vicinity of the container crane, or on the framethereof, for storage of a spreader, since a standby spreader generallyalso has to be available when normal, single spreaders are being used.

After one of the spreaders 5 has thus been uncoupled in this manner, theother spreader 5 is also temporarily uncoupled and set down, whereuponthe frame halves 10 are moved toward each other by activating thecylinders 16. Hoisting frame 1 is herein also displaced slightly intransverse direction in order to place the pick-up eyes 11 into registerwith outer coupling pins 34 of the single remaining spreader 5. After acoupling has then been realized, hoisting frame 1 can be used to pick upsingle containers. Various aspects are shown in FIGS. 4A to 4C, in whicha slightly modified embodiment of the hoisting frame is shown, withdifferently formed bearing cradles 15 and differently placed damping andstabilizing cylinders 18,19.

Although the invention is described above on the basis of an embodiment,it will be apparent that it is not limited thereto. Instead of a frameconsisting of two parts which are displaceable relative to each other intransverse direction, use could thus also be made of a frame havingpick-up means placed on telescopic arms, whereby a spreader constructionacting in transverse direction is in fact obtained.

Instead of the shown pivot arms, other moving mechanisms such astelescopic arms or horizontal shear constructions could also beenvisaged. Combinations of for instance one vertical pivot arm and ahorizontal telescope are also conceivable.

It is of course of no importance for the invention which type ofspreader is suspended under the hoisting frame. In addition to the shown“Long Twin”™ spreader, a normal spreader adjustable in longitudinaldirection or even a fixed frame with twist-locks could also be arranged.

The connection between the hoisting frame and the spreaders can furtherbe embodied in many different ways. In addition to the shown slidingpins and eyes, twist-lock connections can for instance also beenvisaged. A plurality of pick-up eyes could also be arranged, wherebyeach spreader would be picked up at two points lying at a distance fromeach other in transverse direction, even when the hoisting frame is usedin the extended position with two spreaders.

Finally, it is of course also possible to extend the inventive conceptfrom two to three or more spreaders, wherein one hoisting frame could besuitable for picking up two spreaders in a retracted position and threespreaders in an extended position, or could even be varied betweenpositions in which one, two or three spreaders are picked up.

The scope of the invention is therefore defined solely by the appendedclaims.

1. Hoisting frame for transferring containers, the hoisting framecomprising: means, arranged on an upper side of the frame, forconnecting the frame to at least two hoisting cables suspended at amutual distance in a longitudinal direction of the hoisting frame; andmeans, arranged on an underside of the frame, for picking up at leastone secondary hoisting frame, which secondary hoisting frame hastwist-locks for picking up at least one container, a transversedimension of the secondary hoisting frame corresponding substantiallywith a transverse dimension of a container, wherein the frame isadjustable in a transverse direction between a retracted position, inwhich a transverse dimension of the frame is at most equal to that ofthe secondary hoisting frame and the container, and an extended positionin which the transverse dimension is larger than that of the secondaryhoisting frame, the frame being divided in the longitudinal directioninto frame parts that are movable relative to each other at least in atransverse direction, and wherein the means for picking up are forpicking up a single secondary hoisting frame in the retracted positionand for picking up two mutually adjacent secondary hoisting frames inthe extended position, the means for picking up including a plurality ofpick-up elements distributed on the frame parts and the pick-up elementson one of the frame parts cooperating with the pick-up elements onanother one of the frame parts for picking up the single secondaryhoisting frame when the frame parts are moved toward each other to theretracted position of the frame.
 2. Hoisting frame as claimed in claim1, further comprising: controllable means for moving the frame partsaway from and toward each other.
 3. Hoisting frame as claimed in claim2, wherein the controllable means includes at least one member ofadjustable length which connects the frame parts.
 4. Hoisting frame asclaimed in claim 3, wherein the controllable means includes at least oneactuator co-acting with the at least one connecting member.
 5. Hoistingframe as claimed in claim 4, wherein at least one pivotable arm isconnected to the frame part via a pivot, and the actuator is arrangedbetween the arm and the pivot.
 6. Hoisting frame as claimed in claim 4,wherein the at least one connecting member is a pivotable arm. 7.Hoisting frame as claimed in claim 3, wherein the at least oneconnecting member is a pivotable arm.
 8. Hoisting frame as claimed inclaim 7, wherein the arm is pivotable substantially parallel to a mainplane of the hoisting frame.
 9. Hoisting frame as claimed in claim 8,wherein the at least one pivotable arm is connected to the frame partvia a pivot, and the actuator is arranged between the arm and the pivot.10. Hoisting frame as claimed in claim 7, wherein at least two pivotablearms are included, each moveable by at least one associated actuator.11. Hoisting frame as claimed in claim 10, wherein at least twoactuators are connected to at least one of the pivotable arms. 12.Hoisting frame as claimed in claim 11, wherein the pivotable arms arearranged substantially symmetrically relative to a transverse centreline of the hoisting frame, and wherein the arms on opposite sides ofthe hoisting frame are pivotable in opposite directions.
 13. Hoistingframe as claimed in claim 10, wherein the pivotable arms are arrangedsubstantially symmetrically relative to a transverse centre line of thehoisting frame, and wherein the arms on opposite sides of the hoistingframe are pivotable in opposite directions.
 14. Hoisting frame asclaimed in claim 7, wherein each pivotable arm is substantiallysymmetrical relative to a longitudinal centre line of the hoistingframe.
 15. Hoisting frame as claimed in claim 7, wherein the at leastone pivotable arm is connected to the frame part via a pivot, and theactuator is arranged between the arm and the pivot.
 16. Hoisting frameas claimed in claim 1, wherein the connecting means are for connectingthe hoisting frame to at least two pairs of hoisting cables suspended ata distance from each other in the longitudinal direction of the hoistingframe, and are divided in the longitudinal direction such that eachframe part is connectable to at least two hoisting cables.
 17. Hoistingframe as claimed in claim 16, wherein the connecting means includescable pulleys, and wherein each frame part carries at least two cablepulleys placed at a distance from each other in longitudinal direction.18. Hoisting frame as claimed in claim 17, wherein the pick-up elementsare placed substantially straight under the cable pulleys in theextended position of the hoisting frame.
 19. Hoisting frame as claimedin claim 17, further comprising at least one actuator arranged betweenthe rotation axis of one of the cable pulleys and the frame part. 20.Hoisting frame as claimed in claim 1, wherein the extended position theframe is adjustable in the transverse direction in order to vary a spacebetween the two secondary hoisting frames.
 21. Hoisting frame as claimedin claim 1, wherein the frame parts are pivotable relative to each otherin the plane of the hoisting frame.
 22. Hoisting frame as claimed inclaim 1, wherein the frame parts are pivotable relative to each othertransversely of the plane of the hoisting frame.
 23. Hoisting frame asclaimed in claim 22, further comprising at least one actuator arrangedbetween the rotation axis of one of the cable pulleys and the framepart.
 24. Hoisting frame as claimed in claim 1, wherein the frame partsare movable relative to each other in the longitudinal direction. 25.Hoisting frame as claimed in claim 1, wherein the secondary hoistingframe is adjustable in the longitudinal direction.
 26. Method fortransferring loads, comprising the steps of: a) lowering a hoistingframe as claimed in claim 1 at a first location, b) picking up one loadat the first location when the hoisting frame is retracted, or two loadswhen the hoisting frame is extended, c) lifting the hoisting frame withthe picked-up at least one load, d) displacing the hoisting frame withthe picked-up at least one load to a second location, e) lowering thehoisting frame with the picked-up at least one load at the secondlocation, f) uncoupling the at least one load from the hoisting frame,g) lifting the hoisting frame, h) moving the hoisting frame from itsretracted to its extended position or from its extended to its retractedposition, wherein a secondary hoisting frame is coupled on or uncoupled,and i) repeating steps (a) to (g).
 27. Method as claimed in claim 26,wherein the method is for transferring containers.
 28. Combination of aprimary hoisting frame and at least one secondary hoisting frame,wherein the primary hoisting frame comprises: means, arranged on anupper side of the frame, for connecting the frame to at least twohoisting cables suspended at a mutual distance in a longitudinaldirection of the hoisting frame; and means arranged on an underside ofthe frame, for picking up the at least one secondary hoisting frame; andwherein the at least one secondary hoisting frame comprises twist-locksfor picking up at least one container, the at least one secondaryhoisting frame having a transverse dimension that is substantially equalto a transverse dimension of the at least one container; wherein theprimary hosting frame is adjustable in a transverse direction between aretracted position, in which a transverse dimension of the frame is atmost equal to that of the at least one secondary hoisting frame and theleast one container, and an extended position in which the transversedimension is larger than that of the at least one secondary hoistingframe, and wherein the means for picking up are for picking up a singlesecondary hoisting frame in the retracted position and for picking uptwo mutually adjacent secondary hoisting frames in the extendedposition.
 29. Combination as claimed in claim 28, wherein the primaryhoisting frame is divided in the longitudinal direction into the frameparts that are movable relative to each other at least in the transversedirection and the means for picking up includes a number of pick-upelements distributed over the frame parts.
 30. Combination as claimed inclaim 29, further comprising: controllable means for moving the frameparts from and toward each other.
 31. Combination as claimed in claim30, wherein the controllable means includes at least one member ofadjustable length which connects the frame parts.
 32. Combination asclaimed in claim 31, wherein the controllable means includes at leastone actuator co-acting with the at least one connecting member. 33.Combination as claimed in claim 32, wherein the at least one connectingmember is a pivotable arm.